mochi-mochi61 https://blog.hatena.ne.jp/mochi-mochi61/ 数学大好き宣言！ https://mochi-mochi61.hatenablog.com/ 日記メモ ・算術幾何平均を使った円周率の近似：a_0=1, b_0=1/√2, S_0=1/4, a_{n+1}=(a_n+b_n)/2, b_{n+1}=√(a_n+b_n), S_{n+1}=S_n+2^n(a_{n+1}^2+b_{n+1}^2)とおくと、n→∞のときS_n→πらしい。 ・漸化式a_{n+2}=Aa_{n+1}+Ba_nを満たす数列a_nにおいて、b_n=a_{n+1}/a_n とおくと、b_{n+1}=a_{n+2}/a_{n+1}=(Aa_{n+1}+Ba_n)/a_{n+1} =A+B/b_n. b_n=a_n/a_{n+1}とおくと、b_{n+1}=a_{n+1}/(Aa_… 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fmochi-mochi61.hatenablog.com%2Fentry%2F2021%2F03%2F09%2F203038" title="(3/9~)メモ - 数学大好き宣言！" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> Hatena Blog https://hatena.blog 2021-03-09 20:30:38 rich https://mochi-mochi61.hatenablog.com/entry/2021/03/09/203038 1.0 100%